Coordinate measuring machines (CMMs) have been used for many years to accurately measure a wide variety of work pieces. For example, CMMs can measure critical dimensions of aircraft engine components, surgical tools, and gun barrels. Precise and accurate measurements help ensure that their underlying systems, such as an aircraft in the case of aircraft components, operate as specified.
Recently, those in the art have begun using computed tomography (CT) systems as CMMs for coordinate metrology. As known by those in the art, a CT system generates three-dimensional images of an object as a function of the attenuation of its x-rays by the object. Their growing acceptance may derive from their ability to obtain details about an object in a way that does not affect or otherwise damage the object.
High production manufacturing, which is an anticipated use for this type of metrology technique, requires rapid dimensional inspection for statistical process control. More specifically, high production manufacturing processes often obtain quantitative results in the form of geometric dimensions, and track those dimensions over time to monitor the efficiency of a production process. To obtain those measurements, the CT system generally reconstructs the object being produced. Undesirably, the process of reconstruction requires many processing steps that handle a great deal of image data. Accordingly, CT measurement systems known to the inventor often are not useful in rapid production lines because they typically take too much time to generate a reconstruction of an object being produced.